The center bearing support is structured such as to elastically support a center bearing (ball bearing) mounted to the outer periphery at a predetermined position in the axial direction of a propeller shaft (not shown) of a motor vehicle to the side of a vehicle body, thereby restricting a vibration of the propeller shaft during traveling, and reducing a vibration transmission between the side of the propeller shaft and the side of the vehicle body.
As shown in FIG. 5, conventionally, as this kind of center bearing support 100, there is a structure in which an outer ring 101 mounted to the side of a vehicle body and an inner ring 102 fitly attached to a center bearing 103 and arranged in the inner periphery thereof are elastically connected via an elastic body 104 formed of an elastomer material.
The elastic body 104 is structured such that a pair of flexible main bodies 104b and 104b formed in a J-like bent shape and being symmetrical with each other in the axial direction extend from both ends in the axial direction of a thick base portion 104a vulcanized and bonded to the inner ring 102, and outer peripheral end portions thereof are pressure inserted and fitted to the inner periphery of the outer ring 101 in a fixing manner. Further, a stopper 104c protruding out to the outer peripheral side between the flexible main bodies 104b and 104b so as to form a taper shape is formed in the base portion 104a. This stopper 104c is structured such as to be in contact with the outer ring 101 at a time when an amplitude of the propeller shaft is increased to be a fixed level or more, thereby to effect buffering.
However, in accordance with the conventional center bearing support, since the stopper 104c is formed in the outer periphery of the base portion 104a of the elastic body 104, as shown by a characteristic graph in FIG. 6, when a displacement of the propeller shaft is further increased after the stopper 104c is in contact with the inner peripheral surface of the outer ring 101 due to a displacement of the propeller shaft in the diametrical direction, a spring constant becomes suddenly high from a certain displacement amount (in this embodiment, near 8 mm), so that there is pointed out a problem that it is impossible to obtain a sufficient shock-absorbing property. This is because the stopper 104c generates a bending deformation at an initial time when it is in contact with the outer ring 101, thereby being soft, however, is exposed to a compression deformation between the outer ring 101 and the base portion 104a of the elastic body 104 at a time of completely falling down, thereby becoming hard.
The present invention is made by taking the problem mentioned above into consideration, and a main technical object thereof is to improve a shock-absorbing property applied by a stopper at a time when a vibration displacement of a supported shaft is increased.